8o SORICID^— SOREX 



canine, lying between the second and third of the series in 

 Myosurus varius {^Journal of Anatomy and Physiology, 1886, 



359)- 



The conspicuous front tooth of the upper jaw (central 



incisor) is stout and hook-like, and is provided pos- 

 teriorly with a large basal cusp or knob ; then follow the 

 five unicuspids formed as compressed triangles. The upper 

 molars have cusps exhibiting a W-shaped pattern. In the 

 lower jaw the first incisor projects horizontally forwards, and 

 has on its upper surface three distinct lobes behind the pro- 

 minent cutting edge ; the smallest tooth in the set follows 

 next to it, the premolar being slightly larger. 



The summits of the teeth are coloured reddish-brown. 



The teeth are well developed and the cranial sutures anchy- 

 losed — in most mammals a true test of maturity — very early in 

 life. The last to close is the basi-occipital suture, which is 

 accordingly the best guide to the age of a specimen. 



Shrews make their first appearance in the Oligocene of 

 North America and Europe (Osborn). The genus Sorex, 

 although, if correctly identified, it is coeval with the sub-family 

 in Europe, is unknown in North America before the Pleistocene 

 (Osborn), and in Britain before the late Pliocene. 



As the result of a recent examination of British fossil 

 shrews, Hinton has found two extinct species in the late 

 pliocene Forest- Bed. One of these, which he names S. savinii, 

 is distinguished as the largest British species hitherto dis- 

 covered ; the other, which he calls S. runtonensis, is a form not 

 much larger than S. mimitus. A third extinct species is known 

 to occur in the pleistocene (Middle Terrace), brickearth of 

 Gray's, Essex, and was almost of the same size as 5". araneus; 

 and still another form, which Hinton names 5. kennardi, has 

 been found recently in a later pleistocene (Third Terrace) 

 deposit at Ponder's End, Middlesex. The latter was inter- 

 mediate in size between S. araneus and 5. minutus, and its skull 

 and jaws present some features which suggest affinity both with 

 the latter species and with 5. alpinus. Hinton's complete 

 descriptions will appear in the Geological Magazine. 



The most nearly allied genera are Soriculus of the Oriental 

 region, without separate orifices for anus and generative organs ; 



